The technology relates to a control device for a hybrid vehicle.
In recent years, hybrid vehicles (HEVs) have been in practical use. Hybrid vehicles include engines and electric motors as driving sources. Some hybrid vehicles include continuously variable transmissions (CVTs) as transmissions, with input clutches provided between the engines and the CVTs, and with output clutches provided between the CVTs and driving wheels. For example, Japanese Unexamined Patent Application Publication (JP-A) No. 2014-231320 discloses a vehicle control device that controls a hybrid vehicle as mentioned above.
In the input clutch, for example, a control of a clutch hydraulic pressure is made, to bring the input clutch to a disengaged state, in order to separate the engine from driving-wheel side, in a motor traveling mode. The motor traveling mode includes traveling solely with the electric motor being driven. In the output clutch, for example, a control of a clutch hydraulic pressure is made, to bring the output clutch to a mildly engaged state, in order to protect the CVT, in a case where a slip or any other incident causes excessive torque to be inputted from the driving wheels. In the mildly engaged state, the excessive torque causes the output clutch to slide. In the CVT, for example, a control of each of pulley hydraulic pressures of a primary pulley and a secondary pulley is made, in order to continuously change a transmission ratio and in order to prevent power transmitting members such as chains from sliding. These controls of the hydraulic pressures include utilizing, for example, solenoid valves, and adjusting the hydraulic pressures by an energization control of the solenoid valves. It is to be noted that normally closed clutches are used, in order to restrain electric power supplied to the solenoid valves or to restrain, for example, heat generation in the solenoid valves. The normally closed clutches are brought to an engaged state during non-energization of the solenoid valves.